Mesabolivar itajai, Huber, 2018

Huber, Bernhard A., 2018, The South American spider genera Mesabolivar and Carapoia (Araneae, Pholcidae): new species and a framework for redrawing generic limits, Zootaxa 4395 (1), pp. 1-178 : 105-106

Mesabolivar itajai sp. n.

Figs 447–448 , 470–480 , 520

Diagnosis. Easily distinguished from known congeners by modifications of male chelicerae ( Figs 472, 475 ; pair of rounded frontal processes), by shape of procursus ( Fig. 471 ; proximally strongly bent towards ventral), and by shape of epigynum ( Figs 476–479 ; unique membranous scape with terminal pocket).

Etymology. The specific name is derived from the type locality; noun in apposition.

Type material. BRAZIL: Santa Catarina: ♂ holotype, 1♀ paratype, UFMG (21528–29), 1♀ paratype, ZFMK (Ar 19197), Serra do Itajaí National Park, 3a Vargem Trail (27.065°S, 49.098°W), ~ 450 m a.s.l., 15.x.2014 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Santa Catarina: 2♀ in pure ethanol, ZFMK (Br 14-150), Serra do Itajaí National Park , Chuva Trail (27.058°S, 49.084°W), 300 m a.s.l., 15.x.2014 (B.A. Huber, L.S. Carvalho).

Description. Male (holotype)

MEASUREMENTS. Total body length 2.7, carapace width 1.1. Distance PME-PME 120 µm, diameter PME 110 µm, distance PME-ALE 100 µm, distance AME-AME 20 µm, diameter AME 40 µm. Sternum width/length: 0.85/ 0.50. Leg 1: 23.5 (5.6 + 0.4 + 5.9 + 10.0 + 1.6), tibia 2: 3.9, tibia 3: 3.0, tibia 4: 5.7; tibia 1 L/d: 59. Femora 1–4 width (at half length): 0.17, 0.17, 0.19, 0.16.

COLOR (in ethanol). Carapace and clypeus ochre-yellow; sternum light brown; legs light brown, without dark or light rings; abdomen dorsally and laterally densely covered with dark bluish marks, ventrally pale greenish gray with large light brown areas in front of gonopore and in front of spinnerets.

BODY. Habitus as in Fig. 447 ; ocular area raised; carapace with shallow but distinct median furrow; clypeus with sclerotized margin but otherwise unmodified; sternum unmodified.

CHELICERAE. With unique pair of large, rounded processes proximally, and pair of smaller pointed apophyses distally in front of laminae ( Figs 472, 475 ).

PALPS. As in Figs 470–471 ; coxa with large retrolateral apophysis; trochanter barely modified; femur proximally slender, without retrolateral apophysis, distally strongly widening and bending towards ventral; tarsus with distinctive dorsal process and one spine; procursus proximally strongly bent towards ventral, distally with complex system of sclerotized and membranous elements ( Figs 473–474 ); genital bulb with large main process partly sclerotized and with small sclerite distally, long semitransparent element originating proximally from main bulbal process.

LEGS. Densely covered with short hairs, without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 4%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~35 pseudosegments, distally fairly distinct.

Female. In general similar to male but slightly darker. Tibia 1 in three females: 4.2, 4.3, 4.4; tibia 4 longer than tibia 1 (4.4–4.6). Epigynum as in Figs 476–479 ; anterior epigynal plate strongly protruding, with distinctive membranous scape directed towards anterior, tip of scape with pocket; posterior plate short and wide, also projecting, with two pairs of spines at lateral margins. Internal genitalia as in Figs 480 , 520 , with pair of elongated pore-plates diverging anteriorly.

Natural history. The spiders were found in leaf litter and small cavities in the ground. When disturbed, they vibrated with high frequency and small amplitude.

Distribution. Known from type locality in Santa Catarina state ( Brazil) only ( Fig. 738 ).

Figures

FIGURES 447–458. Live specimens, Mesabolivar difficilis group (part 1). 447–448. M. itajai sp. n., male and female from Itajaí.449–451.M.niteroi sp. n., males and female from St.Hilaire/Lange. 452–453. M.saci sp. n., male and female from São Joaquim. 454–456. M. constrictus sp. n., males (regular color and white abdomen morph) and female from Três Barras. 457– 458.M.sepitus sp. n., male and female from Serra Geral.

FIGURES470–475. Mesabolivar itajai sp. n. (UFMG 21528).470–471. Left male palp, prolateral and retrolateral views.472, 475. Male chelicerae, frontal and lateral views. 473–474. Left procursus, prolateral and dorsal views. Scale lines: 0.5 (470– 471), 0.3 (472–475).

FIGURES 476–480. Mesabolivar itajai sp. n. (ZFMK Ar 19197). 476–479. Epigynum, ventral, frontal, posterior, and lateral views.480.Cleared female genitalia, dorsal view.Scale lines: 0.3.

FIGURES 520–537. Female epigyna in various views and cleared female genitalia in dorsal views, Mesabolivar difficilis group. 520. M. itajai sp. n. (ZFMK Ar 19197). 521. M. niteroi sp. n. (ZFMK Ar 19198). 522–524. M.difficilis (Mello-Leitão, 1918) (ZFMK Ar 19201), epigyna in lateral, frontal, and posterior (slightly ventral) views. 525–530. M. sp. (“M. difficilis” in Bonaldo et al. 2009) from Presidente Figueiredo (525–527, ZFMK Ar 19205) and from Manaus (528–530, SMNK-ARA 12794) (522–530 at same scale and in same views). 531. M. saci sp. n. (ZFMK Ar 19207). 532. M. constrictus sp. n. (ZFMK Ar 19208). 533. M. sepitus sp. n. (ZFMK Ar 19210). 534–537. M. cavicelatus Machado et al., 2007 (epigyna: ventral views), from Penedo (534–535, ZFMK Ar19215) and from Ubatuba (536–537, ZFMK Ar 19218).

FIGURES 738–739. Known distribution of the Mesabolivar difficilis group.